Known electrical explosive systems commonly comprise an electrical pulse generator, a length of cable connected to the electrical pulse generator, and an electrical initiator of an explosive charge connected to the length of cable.
Known explosive arrangements comprising two or more explosive charges may require one of the charges to be initiated before another one of the explosive charges. A tandem charge shell may comprise a shaped charge that is initiated to penetrate an object, and a secondary charge that is initiated a fixed time delay after the first charge has been initiated, for example as described in U.S. Pat. No. 5,198,615.
In an alternative situation, a set of demolition charges may be placed around a structure to be demolished with a requirement that one of the explosive charges is initiated before another of the explosive charges, to assure proper demolition of the structure.
Timing delays between initiations of explosive charges may be implemented using variable lengths of fuze, although, the accuracy of the time delay provided by variable lengths of fuze is fairly low.
A known method for electrically initiating a secondary charge of a tandem warhead comprises the use of a piezoelectric material that becomes compressed as a result of a primary charge being initiated, and generates an electrical pulse that initiates the secondary charge. However, the time at which the primary charge is initiated is determined by impact of the warhead with an object, and the length of time until the secondary charge is initiated is short and not well-defined.
Another known method for demolition charges is to use a sequenced electrical pulse generator that sends an electric pulse to one output connected to one explosive charge, and a slightly later electric pulse to another output having another explosive charge. However, then multiple long lengths of cable are required to go between the sequenced electrical pulse generator and the explosive charges; specifically one long length of cable (e.g. 50 m) for each explosive charge that is used. Furthermore, each output must transmit a large enough electric pulse to traverse the length of the cable and still have sufficient energy remaining to initiate the explosive charge. A sequenced electrical pulse generator cannot be simply incorporated into an explosive charge system due to the inherent danger of having a source of electrical energy in close proximity to explosives.
It is therefore an aim of the invention to improve upon the known art.